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The Cutting Table · a common question

What measurements do you need for a trapezoid bay window cushion?

Also asked as:How do I measure a bay window seat?What measurements would you need?

Four sides, a depth and a thickness. Leave one out and the quote waits for it.

Answered by

The Pattern Engineer of Detroit ·

The quick answer

Send every edge of the trapezoid: the front, the back, both angled sides and any clipped corners, plus one straight depth and the thickness. Measure each angled side on its own, corner to corner, and take the depth straight down from the highest point to the base line. Add a drawing labeled A, B, C, D, a photo of the seat and any cut-outs.

Dusty rose textured bay window seat cushion on a cream paneled base with a brass floor lamp, botanical prints and cosmosSave
Dusty rose crinkle-textured cushions follow the angles of a cream bay, lit by morning sun.

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Key facts

  • Every edge is measured: front, back, both angled sides and any clipped-corner or short end sides.
  • Depth runs straight from the highest point down to the base line, never along a slanted side.
  • Each angled side is measured separately, corner to corner.
  • On a bay, every breaking point is measured, and cut-outs such as a window handle go on the drawing.
  • A photo of the space and a drawing labeled A, B, C, D are requested; centimeters are preferred.
  • A missing side is asked for before the quote.
  • Very long trapezoids, such as 89 in (226 cm) on the long side, may be suggested in two pieces.

Have it made

Have Nate’s workshop cut this for you

Every edge and both diagonals, to the nearest 1/4 in. If the numbers do not close, the workshop will say so on the call. — Nate

Leave your details and the workshop will call you to confirm measurements, fabric, foam and piping. No prices, dates or payment on this page: it is a request, not an order.

Fabric · Foam · Pipingwhat the workshop will confirm with you

Fabric
The cover cloth: weave, color and care code.
Foam
The core: its density and thickness set the feel.
Piping
The corded seam edge: matching, contrast or none.
Only for this request: no marketing calls or texts. Outside the US, add the country code.
In inches: length × depth × thickness, plus any angles or cut corners.

* Required. A member of the workshop team will call you to talk it through; nothing is charged and nothing is made until you have agreed on every detail with them.

We use these details only to answer this request and make your cushion: your name and contact details, the cushion details and photos you send, the page you came from and the ad or link that brought you, if any. The workshop that makes the cushions receives them. We don't sell them or share them for advertising, and we delete requests after 24 months. Privacy notice for requests.

Nothing is made or charged until you approve the details.

Want to pick the shape and add photos? Use the full quote form

Every number, in the order the cutter reads them

  1. A: the front edge

    Tape along the room side of the seat, end to end.

  2. B: the back edge

    The window side, corner to corner.

  3. C and D: each angled side

    Two separate readings. Never copy one onto the other.

  4. E, F: clipped corners and short ends

    Every small edge of a clipped corner gets its own letter and length. On a bay, so does every breaking point.

  5. The depth

    Straight from the highest point down to the base line, square to the front edge.

  6. The thickness

    The foam height you want. Mark any cut-out, such as a window handle, where it sits.

Why the angled side is never the depth

Here is the mix-up I see most. On an angled bay, the slanted side always runs longer than the straight depth, so a drawing that repeats one number for both will not close. One sketch gave two sides of 43 in (109 cm) each; on that trapezoid they could not both be 43 in, so each side had to be measured on its own.

Another buyer in the US sent 86 in (218 cm) along the top, 126 in (320 cm) along the bottom and 26.5 in (67 cm) on each side. The cutting table worked the depth out from those sides: about 17.4 in (44 cm). Angles are just lengths in disguise. When numbers don't close, the depth is calculated and sent back for you to confirm.

Run your numbers through the trapezoid cushion calculator before you send them. The full method sits in the trapezoid measuring Pattern, and finished seats live under bay window cushions. What does your front edge read, partner?

Long seats, units and the two-piece question

Very long trapezoids, around 79 in (200 cm) or more on the long side, may be suggested in two pieces. For one with an 89 in (226 cm) long side, the workshop asked whether two pieces would be acceptable before quoting it as one. Say in your note whether a split works for you.

Inches are fine. Centimeters are preferred at the cutting table, so if your tape shows both, write both.

A trapezoid cushion with an 86 in top, a 126 in bottom and 26.5 in sides has a straight depth of about 17.4 in, not 26.5 in.

Nate
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Buyer questions

  1. A common question

    What do you need for a clipped-corner trapezoid bay cushion?

    The workshop's answer

    Every edge: front, back, both sides, any small clipped-corner edges, and the depth from the highest point straight down to the base line. If the numbers don't add up, the depth is worked out from the sides and you confirm it. Mark cut-outs such as a window handle too.

  2. A common question

    How should I send measurements for an odd-shaped bay window seat?

    The workshop's answer

    A photo of the space and a drawing with every side labeled A, B, C, D, plus the depth, ideally in centimeters. Measure every breaking point of the bay; a missing side such as D is requested before quoting.

  3. A common question

    Can you make a cushion for my trapezoid bay, and what do you need from me?

    The workshop's answer

    Yes. Send a drawing with every side measured, a photo of the space and the thickness; a size chart is provided. Measure the angled sides separately: on a trapezoid, two sides cannot both be 43 in.

  4. A common question

    Do you cut trapezoid cushions to measure, even long ones?

    The workshop's answer

    Yes. Send every side, including the long one. For a trapezoid with an 89 in (226 cm) long side, the workshop asked whether two pieces would be acceptable before quoting it as a single piece.

Questions buyers ask next

Can I send trapezoid measurements in inches rather than centimeters?

Yes. Buyers in the US send inches and the workshop works from them. Centimeters are preferred at the cutting table, so write both if your tape shows both, and keep every edge in one unit.

Does a bay window cushion have to be symmetrical to be made?

No. Asymmetric bays are fine; the cushion is cut to your drawing. Order on the custom-shape listing, choose the size by depth and overall length, and upload a sketch with every edge and a photo of the seat.

What if my bay has five windows and a lot of angles?

Any number of angles can be made. Sketch every segment with its length and the depth at each breaking point; the workshop turns it into a template for you to check, then you order by the nearest size range and write the full shape in personalization.